Sound-reproducing diaphragm



N. s. FOCHT 1,743,767

SOUND REPRODUCING DIAPHRAGM Filed April 13, 1927 Patented Jan. 14, 1930' UNITED STATES. PATENT 'F' NEVIN snAsHoLrz rocn r, or POTTSTOWN, PENNSYLVANIA SOUfiD-RERRODUCING DIAPHRAGM Application filed April 13,

a degree, nevertheless did not respond tothe -wave frequencies of different-notes in such a way that the sounds audibleto the normal ear were accurately and ,-faithf ully reproduced. That condition-Was largely due to the fact that-"the stiffness of the diaphragm made it more-sensitive to sounds ofhigh pitch Icrfrequency than the ,sounds of low pitch and consequently many of the "low sounds or musicalnotes were lost. Or, on the other 0 "hand if a very flexible diaphragm was used the reproduction of the high notes suffered while the low sound or noteswere more pleasr ingly'rendered. Therefore, considering the past difiicult 0f meeting both the requirements of sti ness and flexibility in one and the same diaphragm, experiments have been made where several diaphragms have been used, each diaphragmbeing sensitive or re s onsive-to vibrations of, certain frequencies, that is, sensitive to a; specified range of vibrations. While this has been found practical in some cases, more especially inradio amplifiers, nevertheless it is. not practical for the general run of talking machines or loud ducer frame,-or Within the casing of a loud speaker of the type generally used in connecmition with household radio receiving sets.

1 Accordingly, one'of the primary objects of the present invention is toprovide a novel diaphragm having the capacity to more ac- 'curately reproduce sounds or notes of both high frequency and low frequency transwhile other parts thereof will respond to high speakers where it is desirable to have a, small 1927. Serial No.-.1a3,511.

mitte'd thereto by a suitable energizer such for example as the needle arm of a talking machine reproducer or the vibrating armw ture of an electrical unit of a radio loud speaker. In that connection it is propo'sed60 to provide'a diaphragm so constructed that the entire diaphragm will readily respond to low notes orsound waves of low frequency notes or sound wavesof higher frequency.

A further object of the invention is to provide asingle diaphragm embodying a plurality of smaller diaphragms arranged eccentrically with reference to the axis of the main diaphragm thereby not to hinder the functioning of the diaphragm as a whole.

lVith the above and otheriobjects in View which will more readily appear as the na- .ture of the invention is better understood,

thesaine consists in thenovel construction, combinat on and arrangement of parts hereinafter more fully described, illustrated and a preferred and practical embodiment 'of the invention is shown in the accompanying drawings in which Fig. 1 is a plan view of the improved diaphragm.

Fig. 2 is a cross sectional view taken on the line 2--2 of Fig. 1. 75

Fig. 3 is across sectional view taken on the line 3-3 of-Fig; 1. 1

Fig. 4 is a ross sectional view taken on the line 4-4 of Fig. 1. 7

Fig. 5 is aside elevation partly in section of a standard electrical loud speaker unit showing the applicationof the'present diaphragm thereto.

Fig. 6 is an elevation of atal'king machine reproducer embodying the diaphragm of 5 .Fig. 1.

Fig. 7 is a detail View illustrating the manne'r ofattaching the arm to the distributing member. v

Fig. 8 is an edge elevation of a talking ma- -stitutes the body of the diaphragm. The

flexibility ofthe diaphragm from the axis B chine reproducer illustrating a modified permits main diaphragm to flex-I.

means for attaching the distributing member to the diaphragm.

\ Fig. 9 is a detail sectional yiew, lilustrating the manner in which the circulap groove I Similar reference characters designate corresponding parts throughout theseveral figures of the drawings.

In carrying the presentinvention into effect it is proposed to provide adiaphragm made of a material and embodymg'structural features. and characteristicsthat will enable it to respond more accurately to the frequency of vibration of both high and low notes, thereby causing va more faithfulreproduction of the sounds than is possible with adiaphragm capable of functioning o'nlyto a more or less restricted frequency of vibration as for example, a single flat diaphragm of uniform thickness throughout. 1 Therefore, according to the present invention it is proposed to incorporate in a single diaphragm the feature of sufficient flexibility to permit of accurate reproduction-of low 'notes'as well as sufficient stiffness-to reproduce faithfully the high notes or soun'ds'of high frequency while all parts of the d1a-- phragmare responsive to the same source of energy.

Referring to the drawings, it will be observed that the diaphragm designated generally as A consists of a circular disk of any suitable and convenient material, preferably duraluminum, or its equivalent, which ,con-

to the periphery C is maintained notwithstanding the f-act that it is provided with the relatively stiffer eccentrically located conical portions D, E and F due to the provision of the radially disposed hinging or flexing channels 1 which produce grooves at the'face of the diaphragm and ribs at the back, said channels communicating with the circular groove 1?. These. channels are of tapering formation having their wide ends at the axis of the diaphragm and their narrow ends opening into the circular flexing groove 1 adjacent the periphery C of said diaphragm. The said groove 1 is spaced from the periphcry of the diaphragm thereby leaving a flat marginal portion 2. to be engaged by the gasket means for holding the diaphragm in' the reproducer frame. This combination of flexing channels and the flexing. groove enables the diaphragm A to flex from its axis said conical portionswh ich constitute aphirality of substantiallyconical subdiaphragms These diaphragms .are pressed out ofthe main body A so that the tips of the conical portions project outwardly from theface of the diaphragm .'to provide the apices 3, 4 and ,5. The bases .of the conical members D, E

and F are not entirely circular as will-be observed from Fig. 1 but are distorted at the side adjacent the'peripheryC of the disk to provide the straight intersecting sides a: and y, resulting in the formation of a flexing rib a extending'from the apex of the cone toward thejunction of thebase lines w and y, and just .touching the inside of 'themain circular flexing groove 1.

I The effect of the cones D, E and F isto provide a plurality of relatively stifi' ,sub-

diaphragms in the main diaphragm which is of relatively greater flexibility due to the provision of the flexing channels 1. The formation of the ribs z permits of sufficient flexibility in the conical portions to enable the sound vibrations of higher frequency to be transmitted to the cones to'be assimilated with theslower vibrations or vibrations of D, E and F presents suflicient inherent stiffness to more faithfully reproduce the sound vibrations of high frequency and short wave len th. j s above explained, the outer end or tip of low frequency imparted to the diaphragm as a whole. Yet, on the other hand, each cone the flexing ribs 9 extend to and touch the ini side of the main circular flexing groove 1? and thereby enable each cone to assimilate and-synchronize the vibrations transmitted to it with the vibrations of the main diaphragm, and also assist in preventing the localization of strains on the cone in a line at right angles to the rib located substantially at the apex of the cone. If each cone hada circular base, the strains and stresses incident tothe vibrations transmitted thereto would have a tendency to-localize such strains in a way that would be harmful to the reproduction of all frequencies of audible sounds, but by forming the conical members -in the manner indicated the main diaphragm A will be able to respond better to its tuned frequencies by reason of the fact that the radially disposed flexing channels will permit maximum flexing of the main diaphragm froni a substan tially marginal point located in the main sound-groove 1 between the tips of theribs 2. That is to say, the main circular groove "1 between the tips ofthe ribs'z will have the capacity to open and close underth'e influence of vibrations transmitted to'thfe main diafphragm in cooperation with the radial flex, I

mg channels 1.

As previously indicated, the axes of the conical members D, E and F are arranged eccentrically to the axis of the main diaphragm A thereby to permit eachcone to remembers D, E and F are made of different I thickness. For example, the conical member D is of slightly greater thickness at the apex 3 than at its base, while the conical members E and F are made with their apical portions 4 and 5 of progressively increasing thickness as will be observed from'Figs. 3' and 1. It will of coursebe understood that in these views the thickness of the metal is somewhat exaggerated for sake of clearness but they will serve to illustrate the idea of providing a plurality of conical members whose walls are of different thickness thereby to give to the several members different degrees of stiffness which will enable each conical member to more readily" receive and translate sound waves of varying frequency.

Each of the apices 3,4 and 5 of the conical members D, E and F is connected with a vibration transmitting and distributing member 6 which performs substantially the functions of a plunger in transmitting to the diaphragm energy produced either by a needle arm when the device is used in a talking machine or the armature of a magnetic device when used as a loud speaker. The distributing member 6 is preferably of spiderlike formation having radially disposed arms 7 which may be directly connected to the apices 3,4 and 5 as shown in Figs. 5 and 6; or, on the other hand, as shown in Fig. 8 the said arms? may be connected to the apices by the posts or pins 8. The function of the arms 7 is to distribute to each of the subdiaphragms a fixed band of wave frequency corresponding to the particular sub-diaphragm to which they are attached. That is to say, the distributing member 6 has its arm or prongs tuned to different frequencies and when it receives sound energy, said energy works off through its proper arm to the subdiaphragm to which it is tuned. In the diaphragmshown in the drawings the sub-diaphragms D, E and F reproduce frequencies from'1,000 to 21,000 vibrations per second,

each cone assuming its quota of that range of frequency to which it is tuned, while the entire diaphragm or main body is responsive to frequencies below 1,000 vibrations per second. The cones or sub-diaphragms there fore translate wave motion occurring in frequency from approximately 1,000 to 21,000 vibrations per second while the main body of the diap ragm translates the plunger action whichmanifests itself in frequencies of below 1,000 vibrations per second;

In Fig. 5 which illustrates the application of the invention to a radio loud speaker unit,

utilizing a standard electrical device, the vibrating armature 9 isconnected to the distributing member 6 by means of the link 10. This link in turn is connected to the armature through the medium of a cushioning member 11, said member being preferably of rubber or equivalent material.

When the diaphragmis used in a talking machine reproducer as shown in Figs. 6, 'i and 8 the distributing member 6 is connected to the needle arm 12 through the medium of a bail or loop 13 carried by the member 6 which is surrounded by a rubber or equivalent gasket or washer'14. In this case one end of the needle arm 12 is bent around the gasket. In both constructions, therefore, the vibrations are transmitted to the diaphragm through a cushioning medium which prevents transmission of metallic sounds to the diaphragm but imparts the full strength of the vibration impulses thereto.

From the foregoing it will be apparent that the novel and distinctive feature of the present invention resides in the provision of a single diaphragm embodying in effect a plurality of diaphragms each having the property of assimilating the transmitting sounds best adapted to it, thereby enabling the reproducer to respond to a wider range of sound frequency and increasing its sensitivity while at the same time augmenting the volume of the sounds reproduced thereby and giving to each sound its more natural tone because of the fact that it is reproduced by means susceptible of flexing and effectually transmitting the frequency to which it is best adapted.

Without further description it is thought that the features and advantages of the in- 1. A sound reproducing diaphragm including a main flexing body and a plurality of substantially conical sub-diaphragms arranged eccentrically to the axis of the main flexing body, and means for transmitting energy to the main flexing body and each of the sub-diaphragms.

2. A sound reproducing diaphragm including a main flexing body and a plurality of substantially conical sub-diaphragms of differential thickness and arran ed eccentrically to the axis of the main iaphragm, and means for transmitting energy to the main flexing body and each of the sub-diaphragms.

3. A sound reproducing diaphragm including a body having a plurality of radially disposed flexing channels, and substantially conical sub-diaphragms formed from the body between said channels, and means for transmitting energy to saidbody and to said sub-diaphragms.

4. A sound reproducing diaphragm in cluding a body having radially disposed flexing channels therein, a plurality of substantially conical sub-diaphragms formed from said body and providing apical portions arranged eccentrically with reference to the axis of the main body, and a vibration distributing, member connected to said apical portions of the cones.

5. A sound reproducing diaphragm including a body having a plurality of tapering flexing channels, the wide ends of said flexing channels being arranged adjacent the axis of the body, and substantially conical sub-diaphragms formed from the body between said flexing channels, and a vibration transmitting and distributing member connected to each of the sub-diaphragms.

6. A sound reproducing diaphragm including a body having a plurality of tapering flexing channels, the wide ends of said flexing channels being arranged adjacent the axis of the body, and substantially conical .subdiaphragms formed from the body between said flexing channels, said sub-diaphragms being provided with a flexing rib lying radially with reference to the axis of the main diaphragm.

7. A sound reproducing diaphragm including a body having a portion thereof eccentric to its axis pressed into the form of a cone to provide a sub-diaphragm responsive to sound vibrations of different frequencies from the main diaphragm.

8. A sound. reproducing diaphragm including a body having portions thereof pressed into substantially conical formation to provide a plurality of sub-diaphragms responsive to sound vibrations of different frequencies from the main diaphragm.

9. A sound reproducing diaphragm including a body having a main flexing groove and a plurality of tapering flexin channels communicating therewith, and su stantially conical sub-diaphragms formed from the body between said flexing channels.

10. A sound reproducing diaphragm including a body having a circular main flexing groove adjacent the periphery thereof and flexing channels disposed radially with reference to the axis of themain diaphragm and communicating with said main flexing groove, and substantially conical sub-diaphragms formed from the body between said flexing channels.

11.'A sound reproducing diaphragm including a body having a' circular main'flexing groove adjacent the periphery thereof {and flexing channels disposed radially with reference to the axis of the main diaphragm and communicating with said main flexing groove, and substantially conical sub-diaphragms formed from thebody between'said flexing channels, and each of said sub-diaphragms being formed with a rib extending from the apex of the sub-diaphragm to the inner edge of said main flexing groove.

12. A sound reproducing means c0mprising a diaphragm including a body embracing within the peripheral edges thereof a plurality of integral areas responsive to sound vibrations of different frequencies, and means for connecting said areas with a source of energy. a

13. A sound reproducing diaphragm, including a body embracing within the peripheral edges thereof a plurality of substantially conical sub-diaphragms, each having a rib portion directed toward the peripheral edge of the body of the diaphragm, and means for transmitting sound produced energy to the apices of the said substantially conical portions.

cluding a body responsive to sound vibrations within a given range and having portions of said body responsive to wave bands of different frequency, and means for transmitting sound produced energy to said diaphragm whereby sounds of low frequency are translated by movement of the entire diaphragm while sounds of higher frequency are translated by said portions of the diaphragm responsive to wave bands of different frequency.

15. A sound reproducing diaphragm, including a body having a plurality of sub-diaphragms each adapted to be connected with a source of energy, and each diaphragm being responsive to a definite wave band of sound frequency.

1.6. A sound reproducing diaphragm, including a bodyv having a plurality of sub-dia phragms each adapted to be connected with a source of energy, and said sub-diaphragms being responsive to different wave bands from 1,000 to 21,000 vibrations per second.

17. A sound reproducing'diaphragm, including a body-having a plurality of sub-diaphragms each adapted to be-connected with a source of energy, and said 'sub-diaphragms being responsive to different wave bands from 1,000 to 21,000 vibrations per second, and-the main body of the diaphragm being responsive to vibrations below 1,000 per second.

18. A sound reproducing diaphragm including a body portion responsive to sound vibrations within a given range of frequency, and portions of said body being formed to provide sub-diaphragms also responsive to sound vibrations of different frequencies within a given range, said range being difi'erent-from the range of sound vibrations to which the body of the diaphragm is responsive, and means for transmitting sound produced energy to each 9f the sub-diaphragms and to the body of the diaphragm.

19. A sound reproducing diaphragm including a mainflexing body and a plurality of sub-diaphragms arranged eccentrically to the axis of the main flexing body, and means for transmitting sound produced energy to each of the sub-diaphragms and to the body 6 of the diaphragm.

20. A sound reproducing diaphragm including a body portion having a plurality of sub-diaphragms formed integrally therewith and arranged eccentrically to the axis of the 10 body of the diaphragm.

In testimony whereof I hereunto afiix my signature.

NEVIN SEASHOLTZ FOOHT. 

